Fix build with gettext-0.22

Building with gettext-0.22 fails for lack of this header:

/usr/bin/msgfmt: input file doesn't contain a header entry with a
charset specification

Patch submitted upstream: https://github.com/brltty/brltty/pull/420

brltty-6.5-gettext.patch

@@ -0,0 +1,41 @@
+Filed upstream as https://github.com/brltty/brltty/pull/420
+
+diff --git a/Messages/ru.po b/Messages/ru.po
+index 6d8c5a7..1bbc931 100644
+--- a/Messages/ru.po
++++ b/Messages/ru.po
+@@ -1,3 +1,34 @@
++# BRLTTY - A background process providing access to the console screen (when in
++#          text mode) for a blind person using a refreshable braille display.
++#
++# Copyright (C) 1995-2022 by The BRLTTY Developers.
++#
++# BRLTTY comes with ABSOLUTELY NO WARRANTY.
++#
++# This is free software, placed under the terms of the
++# GNU Lesser General Public License, as published by the Free Software
++# Foundation; either version 2.1 of the License, or (at your option) any
++# later version. Please see the file LICENSE-LGPL for details.
++#
++# Web Page: http://brltty.app/
++#
++# This software is maintained by Dave Mielke <dave@mielke.cc>.
++#
++msgid ""
++msgstr ""
++"Project-Id-Version: brltty 4.5\n"
++"Report-Msgid-Bugs-To: BRLTTY@brltty.app\n"
++"POT-Creation-Date: 2021-01-27 11:47-0500\n"
++"PO-Revision-Date: 2021-02-07 08:18-0500\n"
++"Last-Translator: Маргарита Мельникова <margaretmelnikova@gmail.com>\n"
++"Language-Team: Friends of BRLTTY <BRLTTY@brlttY.app>\n"
++"Language: ru\n"
++"MIME-Version: 1.0\n"
++"Content-Type: text/plain; charset=UTF-8\n"
++"Content-Transfer-Encoding: 8bit\n"
++"Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && "
++"n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2);\n"
++
+ #: Programs/brltty.c:167
+ #, c-format
+ msgid "\"%s\" started as \"%s\"\n"

brltty.spec

@@ -55,6 +55,8 @@ Source3: brlapi-forbuild.h
 Patch1: brltty-6.3-loadLibrary.patch
 # libspeechd.h moved in latest speech-dispatch (NOT sent upstream)
 Patch2: brltty-6.3-libspeechd.patch
+# fix translations with gettext-0.22: https://github.com/brltty/brltty/pull/420
+Patch3: brltty-6.5-gettext.patch
 Summary: Braille display driver for Linux/Unix
 BuildRequires: byacc
 BuildRequires: glibc-kernheaders
@@ -272,6 +274,7 @@ mv %{name}-%{version} python2
 pushd python2
 %patch1 -p1 -b .loadLibrary
 %patch2 -p1 -b .libspeechd
+%patch3 -p1 -b .gettext
 
 # remove packaged binary file
 rm -f Programs/brltty-ktb